Evaluation of Changes in Muscle Thickness, Bite Force and Facial Asymmetry during Early Treatment of Functional Posterior Crossbite

Objective: To determine morphological and functional effects on masticatory system of early treatment of functional posterior crossbite in young children. Study design: 23 children were divided into two groups:deciduous (DecG, n=11) and early mixed dentition (MixG, n=12), which received slow maxillary expansion. Maximal bite force, ultrasonographic masticatory muscle thickness and facial asymmetry were evaluated in three stages: before the start of treatment (s1), after three months of retention (s2), and after three months of observation (s3). The results were analyzed by Mann-Whitney U-test, correlation test, repeated measures ANOVA and backward stepwise multiple regression. Results. Bite force and temporalis thickness increased from s1 to s2 and s3 in both groups (p<0.05). Body mass index (BMI) increased significantly from s1 to s3 only in the MixG, but the masseter thickness did not differ among the stages. The correlation between the angle of the eye and the angle of the mouth in relation to the mid-sagital plane increased from s1 to s3. Masticatory muscle thickness contributed significantly to bite force magnitude in all stages, whereas age and BMI showed no significant contribution to its variation. Conclusion: Bite force and temporalis muscle thickness increased significantly in children after early treatment of functional crossbite.

Ultrasonography; Bite Force; Face; Malocclusion

1. Malandris M, Mahoney EK. Aetiology, diagnosis and treatment of pos-terior cross-bites in the primary dentition. Int J Paed Dent, 14: 155–166, 2004.

2. Rasheed SA, Prabhu NT, Munshi AK. Electromyographic and ultra-sonographic observations of masseter and anterior temporalis muscles in children. J Clin Pediatr Dent, 20: 127–132, 1996.

3. Sonnesen L, Bakke M, Solow B. Bite force in pre-orthodontic children with unilateral crossbite. Eur J Orthod, 23: 741–749, 2001.

4. Kamegai T, Tatsuki T, Nagano H, Mitsuhashi H, Kumeta J, Tatsuki Y, Kamegai T, Inaba D. A determination of bite force in northern Japanese children. Eur J Orthod, 27: 53–57, 2005.

5. Castelo PM, Gavião MB, Pereira LJ, Bonjardim LR. Masticatory mus-cle thickness, bite force, and occlusal contacts in young children with unilateral posterior crossbite. Eur J Orthod, 29: 149–156, 2007.

6. Kiliaridis S, Katsaros C, Raadsheer MC, Mahboubi PH. Bilateral mas-seter muscle thickness in growing individuals with unilateral crossbite. J Dent Res, 79: 497 [abstract 2831], 2000.

7. Allen D, Rebellato J, Sheats R, Ceron AM. Skeletal and dental contri-butions to posterior crossbites. Angle Orthod, 73: 515–524, 2003.

8. Brin I, Ben-Bassat Y, Blustein Y, Ehrlich J, Hochman N, Marmary Y, Yaffe A. Skeletal and functional effects of treatment for unilateral pos-terior crossbite. Am J Orthod Dentofacial Orthop, 109: 173–179, 1996.

9. Pinto AS, Buschang PH, Throckmorton GS, Chen P. Morphological and positional asymmetries of young children with functional unilateral posterior crossbite. Am J Orthod Dentofacial Orthop, 120: 513–520, 2001.

10. Saitoh I, Hayasaki H, Iwase Y, Nakata M. Improvement in jaw motion following treatment of unilateral crossbite in a child with primary den-tition: a case report. J Craniomand Pract, 20: 129–134, 2002.

11. Ahlgren J. Pattern of chewing and malocclusion of teeth. A clinical study. Acta Odontol Scand, 25: 3–13, 1967.

12. Wickwire NA, Gibbs CH, Jacobson AP, Lundeen HC. Chewing pat-terns in normal children. Angle Orthod, 51: 48–60, 1981.

13. Marinelli A, Alarashi M, Defraia E, Antonini A, Tollaro I. Tooth wear in the mixed dentition: a comparative study between children born in the 1950s and the 1990s. Angle Orthod, 75: 318–321, 2005.

14. Machado Jr AJ, Crespo NA. Cephalometric study of alterations induced by maxillary slow expansion in adults. Rev Bras Otorrinolaringol, 72: 166–172, 2006.

15. Petrén S, Bondemark L, Soderfeldt B. A systematic review concerning early orthodontic treatment of unilateral posterior crossbite. Angle Orthod, 73: 588–596, 2003.

16. Bonjardim LR, Gavião MB, Carmagnani FG, Pereira LJ, Castelo PM. Signs and symptoms of temporomandibular joint dysfunction in chil-dren with primary dentition. J Clin Pediatr Dent, 28: 53–58, 2003.

17. Šlaj M, Ješina MA, Lauc T, Rajić-Meštrović S, Mikšić M. Longitudinal dental arch changes in the mixed dentition. Angle Orthod, 73: 509–514, 2003.

18. Boysen B, La Cour K, Athanasiou AT, Gjessing PE. Three-dimensional evaluation of dentoskeletal changes by quad-helix or removable appli-ances. Br J Orthod, 19: 97–107, 1992.

19. Ferrario VF, Sforza C, Miani A, Tartaglia G. Craniofacial morphometry by photographic evaluations. Am J Orthod Dentofacial Orthop, 103: 327–337, 1993.

20. Bishara SE, Jorgensen GJ, Jakobsen JR. Changes in facial dimensions assessed from lateral and frontal photographs. Part I – Methodology. Am J Orthod Dentofacial Orthop, 108: 389–393, 1995.

21. Pompei VTM, Carvalho AS, Cunha FL, Pompei-Filho H. Evaluation of face asymmetry in individuals with posterior crossbite through frontal photographs. Ortodontia, 38: 337–344, 2005 (in portuguese).

22. Erdinc A, Ugur T, Erbay E. A comparison of different treatment tech-niques for posterior crossbite in the mixed dentition. Am J Orthod Dentofacial Orthop, 116: 287–300, 1999.

23. Kiliaridis S, Mahboubi PH, Raadsheer MC, Katsaros C. Ultrasono-graphic thickness of the masseter muscle in growing individuals with unilateral crossbite. Angle Orthod, 77: 607–611, 2007.

24. Sonnesen L, Bakke M. Bite force in children with unilateral crossbite before and after orthodontic treatment. A prospective longitudinal study. Eur J Orthod 29:310-313, 2007.

25. Chung CH, Font B. Skeletal and dental changes in the sagittal, vertical, and transverse dimensions after rapid palatal expansion. Am J Orthod Dentofacial Orthop, 126: 569–575, 2004.

26. Bakke M, Michler L, Møller E. Clinical significance of isometric bite force versus electrical activity in temporal and masseter muscles. Scand J Dent Res, 97: 539–551, 1989.

27. Kiliaridis S. Muscle function as a determinant of mandibular growth in normal and hypocalcaemic rat. Eur J Orthod, 11: 298–308, 1989.

28. Sonnesen L, Bakke M. Molar bite force in relation to occlusion, cran-iofacial dimensions, and head posture in pre-orthodontic children. Eur J Orthod, 27: 58–63, 2005.

29. Shiau Y-Y, Wang J-S. The effects of dental condition on hand strength and maximum bite force. J Craniomand Pract, 11: 48–54, 1993.

30. Raadsheer MC, van Eijden TM, van Ginkel FC, Prahl-Andersen B. Contribution of jaw muscle size and craniofacial morphology to human bite force magnitude. J Dent Res, 78: 31–42, 1999.

31. Rentes AM, Gavião MB, Amaral JR. Bite force determination in chil-dren with primary dentition. J Oral Rehabil, 29: 1174–1180, 2002.

32. Tabe H, Ueda HM, Kato M, Nagaoka K, Nakashima Y, Matsumoto E, Shikata N, Tanne K. Influence of functional appliances on masticatory muscle activity. Angle Orthod, 75: 616–246, 2005.

33. Braun S, Bantleon HP, Hnat WP, Freudenthaler JW, Marcotte MR, Johnson BE. A study of bite force, part 1: Relationship to various phys-ical characteristics. Angle Orthod, 65: 367–372, 1995.

34. Linderholm H, Lindqvist B, Ringvist M, Wennström A. Isometric bite force in children and its relation to body built and general muscle force. Acta Odontol Scand, 29: 563–568, 1971.

35. Troelstrup B, Møller E. Electromyography of the temporalis and mas-seter muscles in children with unilateral cross-bite. Scand J Dent Res, 78: 425–430, 1970.

36. Georgiakaki I, Tortopidis D, Garefis P, Kiliaridis S. Ultrasonographic thickness and electromyographic activity of masseter muscle of human females. J Oral Rehabil, 34: 121–128, 2007.

37. Langberg BJ, Arai K, Miner RM. Transverse skeletal and dental asym-metry in adults with unilateral lingual posterior crossbite. Am J Orthod Dentofacial Orthop, 127: 6–15, 2005.

38. Padwa BL, Kaiser MO, Kaban LB. Occlusal cant in the frontal plane as a reflection of facial asymmetry. J Oral Maxillofac Surg, 55: 811–816, 1997.

39. Bishara SE, Burkey PS, Kharouf JG. Dental and facial asymmetries: a review. Angle Orthod, 64: 89–98, 1993.